Fu, Yunyi
Professor
Research Interests: Carbon-based nanoelectronics
Office Phone: 86-10-6275 2925
Email: yyfu@pku.edu.cn
Fu, Yunyi is a professor in the Institute of Micro-/Nanoelectronics, School of EECS. He received a Ph.D. degree in materials from Shanghai Jiao Tong University (SJTU) in 1998, and then worked as a postdoctoral researcher at University of Science and Technology Beijing(1998-2000), and Department of Physics in Peking University(2000-2002). He was JSPS Research Fellow at Tohoku University in Japan (2006) and a visiting scholar at the Hong Kong University of Science & Technology (2008). His recent work focuses on carbon-based nanoelectronics, including memories, RF-FETs, via interconnects and transmission-lines.
Dr. Fu has published more than 50 research papers and 40 patents. His main research works are summarized as follows:
(1) Electrical transport behavior of C70 fullerene peapod: We report the first detailed studies of the electrical transport behavior of C70 fullerene peapod bundles at various temperatures from 400 K down to 4 K. With electrical breakdown, ambipolar (i.e. both p- and n-type) field-effect transistors (FETs) based on fullerene peapod with high performance have been realized. This work focuses on the role of the Schottky barrier and the thermal activation energy in the transport behavior of fullerene bundles. The temperature dependence of our measurements reveals that transport is dominated by thermally assisted tunnelling in fullerene bundles at low temperature. We also investigated the gate-controlled rectification behavior in C70@SWNT networks at room temperature in air, which demonstrates a strategy for diode fabrication based on peapod networks.
(2) Memory devices of SWNTs: Two-bit memory devices based on single-walled carbon nanotubes(SWNTs) have been demonstrated. We found that the pertinent memory behaviours originate from the capacitive effect due to polarization of molecules, especially the surface-bound water molecules on SiO2 in close proximity to carbon nanotubes. Our investigations are intimately linked with ultrahigh-density memory applications, and possibly go a long way in broadening the memory applications of SWNTs, for example from nonvolatile to volatile cells.
(3) Carbon-based active and passive devices: Top-gated RF transistors using millimeter-scale single graphene domain on a SiO2/Si substrate have been demonstrated through a conventional microfabrication process. A maximum cut-off frequency of 178 GHz and a peak maximum oscillation frequency of 35 GHz are achieved in the graphene-domain-based FET with a gate length of 50 nm and 150 nm, respectively. In addition, a low-resistance graphite CPWs with effective graphite length up to 200 lm have also been fabricated. A record low insertion loss of graphite CPW (2.76 dB/100 lm) is demonstrated, and the average insertion loss of our graphite CPWs is only 1/5 of that of our monolayer graphene CPWs. We also invented a reliable method to create SWNTs via interconnects using alternating dielectrophoresis (DEP). SWNTs are vertically assembled in the microscale via-holes successfully at room temperature under ambient condition. We also propose and test possible approaches to reducing the contact resistance between CNT vias and metal electrodes.
